Abstract: Based on the observations on N₂O emission from rice-wheat rotation systems in Southeast China,its temporal variation and the effects of fertilization,irrigation,temperature,and soil moisture and available Ncontents on it are discussed. Meanwhile,the difference of CH₄ and N₂O emissions from rice season is analysed. The results show that the amount of N₂O emitted from rice season only accounts for about 30% of the whole rotation cycle.The CH₄ emission increases 26% by keeping flooding in rice season,and N₂O emission from rice-wheat rotation cycle reduces 13～26%,comparing to normal irrigation.

Key words: N₂O emission, Temporal variation, Regulating factor, CH₄ emission, Rice wheat rotation system, seedling, age structure, slope aspect, Juglans cathayensis, growth